We are engaged in establishing reproducible methodologies for the largest scale production of human fibroblastoid interferon (a weekly production of 5 x 10 to the 8th power units referenced to the NIH interferon standard). Only with these amounts is it feasible to evaluate the antiviral, antitumor and cell growth inhibitory properties of human fibroblastoid interferon. During the course of this investigation it is also intended to obtain radioactively labelled interferon and monospecific antibodies to interferons as useful probes for the studies stated herein. BIBLIOGRAPHIC REFERENCES: Tan, Y.H. and W. Berthold. (1977) A mechanism for the induction and regulation of human fibroblastoid interfereon genetic expression. J. Gen. Virol. 34: 401-411. Cupples, C. and Y.H. Tan. (1977) Effect of human interferon preparations on lymphoblastogenesis in Down's syndrome. Nature 267: 165-167.